Oops, can't edit comment. Just wanted to add that Posterous also had that feature but the syntax was different.
#!javascript
alert('woohoo');
I really wish there was only one way to do it all over the place.

Markdown is a simple little humane markup language based on time-tested plain text conventions from the last 40 years of computing. Meaning, if you enter this… …you get this! Lightweight Markup Languages ============================ According to **Wikipedia**: > A [lightweight markup lan...

The one feature I truly miss in some Markdown implementations is the ability to specify code block language. For example on Github, I can do:
```javascript
alert('woohoo');
```
And the code block will be syntax highlighted for Javascript.

Markdown is a simple little humane markup language based on time-tested plain text conventions from the last 40 years of computing. Meaning, if you enter this… …you get this! Lightweight Markup Languages ============================ According to **Wikipedia**: > A [lightweight markup lan...